jerasure.c: fix memory leak in error case
jerasure.c: fix memory leak in error case

Check matrix for NULL before call talloc().

CID 1093213 (#1 of 1): Resource leak (RESOURCE_LEAK)
 4. leaked_storage: Variable "bitmatrix" going out of scope
 leaks the storage it points to.

Signed-off-by: Danny Al-Gaaf <473e39ac77cf392f0dd9bacde8409de76c14d006@bisect.de>

cedricde/jerasure,leo-project/jerasure,ceph/jerasure,windkit/jerasure,tsuraan/Jerasure,cedricde/jerasure,tsuraan/Jerasure